Conventionally, a variety of methods have been proposed for projecting a three-dimensional video image to three-dimensionally show a video image. In particular, recently, owing to the promotion of technology development of various types of equipment, there have been proposed methods for projecting a three-dimensional image, using three-dimensional liquid crystal display devices or liquid-crystal shutter glasses as well as anagraphs employing so called three-dimensional viewing glasses using conventionally known blue and red films. Further, projection of three-dimensional video images using holograms becomes also known as a “practical-level” technique. Lately, in place of such blue and red films, there have also been employed three-dimensional viewing glasses having provided thereon two types of polarizing filters of which polarizing conditions are different from each other.
However, in such a method for projecting three-dimensional video images, in the case of constructing a system which realizes simultaneous viewing at a comparatively modest price and by a large number of viewers, the projecting method using three-dimensional viewing glasses is cost-efficient, and has been utilized in planetariums or the like.
Further, there has been proposed a simulation ride device for projecting video images from a plurality of projectors on screens formed in the recessed spherical shape instead of three-dimensional video images, thereby displaying high-definition, three-dimensional video images (see Patent Document 1, for example).    Patent Document 1: Japanese Laid-open Patent Application No. 2000-132082